Smart Contract Development — landing page (evm/development/index)

**Page:** `evm/development/index.mdx`

**Context:** ~11 written siblings (`compiling`, `creating`, `deploying`, `verifying`, `gas-fees`, `rent`, `security`, `addresses`, `forking`, `traceability`, `archive-queries`, `json-rpc/`).

**Scope:** Section overview that walks the contract lifecycle (create → compile → deploy → verify → maintain) and routes into the siblings.

### Acceptance criteria
- [ ] Replace the placeholder template with a real landing page
- [ ] Remove `hidden: true` from the frontmatter
- [ ] **No "Browse by section" block** — the side nav covers that; open straight into the deep-dive sections
- [ ] Route into the written sibling pages via ``/``
- [ ] Follow the style guide (markdown tables only; no AI-tell phrasing)